Let us travel the 65-mile length of the Columbia River Gorge for a closer look at the rock formations and geology of the area. We will supplement our observations with information from the literature on the...

This report presents a summary of the principal geologic and physiographic features of the upper part of the Snake River Canyon between Oregon and Idaho. The area discussed extends from Farewell Bend near...

Grand Canyon National Park is a geologic experience like no other. Each year, many of the park's 5 million visitors attend ranger-led interpretive programs to learn how the spectacular scenery formed. It is...

Introduction -- Stratigraphy -- Nye mudstone -- Astoria Formation -- Unnamed unit -- Age of Miocene sequence -- Foraminiferal fauna -- Molluscan fauna -- References